WSP07079

• File Number: 8272.100.60
• Description: Colorado River Basin Salinity Control Forum
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 8/1/1992
• Author: CRBSCF
• Title: 1991 Annual Progress Report - Water Quality Standards for Salinity - Colorado River System - August 1992
• Water Supply Pro - Doc Type: Annual Report

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WATER SUPPLY

The natural (undepleted and unregulated) flow at Lee Ferry, as
determined by the U.S. Bureau of Reclamation (Reclamation) for the
water years 1973 through 1991 is shown on Table 1.

TABLE 1
NATURAL FLOW AT LEE FERRY

Water Year

Natural Flow (maf)*

1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991

19,435,000
13,307,000
16,150,000
10,723,000
5,023,000
14,660,000
17,337,000
16,935,000
7,413,000
16,108,000
23,647,000
23,511,000
20,163,000
21,883,000
16,924,000
11,581,000
9,107,000
8,662,000
11,399,000

NOTE: 1986-91 are preliminary, subject to revision.

* Million acre-feet

The natural flow for 1977 at Lee Ferry of 5.0 million acre-
feet (maf) was the driest year on record for the period 1906-1991,
and 1983, with a flow of 23.6 maf, was the wettest. The long-term
mean natural flow for the period 1906-1991 is 15 million acre-feet.
The period 1983 through 1986 was a period of significantly above-
normal runoff. Each of those four years had a natural flow in
excess of 20.0 maf, with a four year average of 22.3 maf. Only
once before, in 1920 and 1921 did 20.0 maf of natural flow occur
for two or more consecutive years and only one other period (1920-
1923) had an average natural flow exceeding 20.0 maf (20.4 maf).
From 1988 through the 1991 water years flows have been well below
normal. Preliminary data indicates that natural flow at Lee Ferry
for water year 1991 is about 75 percent of normal.

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